As one say creation for "the act of creating something", couldn't the word edition mean "the act of changing something"? I was under the impression it was the case. But a remark from one of my colleagues, telling me I should use editing instead, prompted me to check on Wiktionary. As it turned out, I didn't find the meaning I searched under the definitions. Note that my colleague and I both are not native speakers. So which of us is right?
Your colleague is correct. Though it would make sense for edition to mean editing, it has come only to mean the result of the editing (e.g. second edition) or the format of the finished work (e.g. leather-bound edition).
It would be better to use editing or revising.
I would recommend the term "emendation" for this purpose.
For example: "Emendation of the injured text was made to restore sense."
The advantage of using "emend" in this way is that it is often more value-neutral, where "edit" has a somewhat critical nuance that may be unwanted.
"Creation" means the result of creating something, not the act of creating something. The act, I suppose, would be a gerund like "creating."
"Edition" also means the result of editing something, however, its idiomatic usage would be significant collection of edits, pulled together into a whole. This comes from the historical background of printing, where creating a new version of a book is time consuming and expensive. If John Grisham's latest novel has a spelling error on page 63, then the printer is not going to recall all those books to correct this. Rather, on the second printing they will correct this and other collected changes, and this would be a new edition.
Modern fast online publishing don't have this problem, though they do have a different problem -- a constantly changing document is hard to refer to. For this reason many technical documents are still issued in editions/versions, so that everyone has a common reference to talk about. Of course a word document is a lot cheaper to version than a paper book, but version numbers serve a different purpose in that case.
In terms of your question, It has become common to refer to a small scale change to a text as simply "an edit." I have never heard such a change referred to as "an editing", in fact, it sounds pretty foreign to me. "Emendation" sounds really formal to me too. No doubt it is correct, but I just don't hear it used very much, but that might just be me.